13666321 has 2 divisors, whose sum is σ = 13666322. Its totient is φ = 13666320.

The previous prime is 13666309. The next prime is 13666369. The reversal of 13666321 is 12366631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13608721 + 57600 = 3689^2 + 240^2 .

It is an emirp because it is prime and its reverse (12366631) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13666321 - 2⁷ = 13666193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13666321.

It is not a weakly prime, because it can be changed into another prime (13666391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6833160 + 6833161.

It is an arithmetic number, because the mean of its divisors is an integer number (6833161).

Almost surely, 2^13666321 is an apocalyptic number.

It is an amenable number.

13666321 is a deficient number, since it is larger than the sum of its proper divisors (1).

13666321 is an equidigital number, since it uses as much as digits as its factorization.

13666321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 28.

The square root of 13666321 is about 3696.7987502703. The cubic root of 13666321 is about 239.0840142769.

The spelling of 13666321 in words is "thirteen million, six hundred sixty-six thousand, three hundred twenty-one".